Other good hotels include:
Xara Palace in Mdina, a boutique converted Palazzo on the bastions of the "silent city". Fantastic views of most of the island as this is one of the highest points on the island. This is the preferred location for movie stars when they're filming in Malta. No pools here, but lovely private outdoor jacuzzis with phenomenal views. The De Mondion restaurant is considered the best in the Island.

The Corinthia in Attard, lovely old-school style colonial hotel (with a reason pool). Fairly quiet area, but next to the San Anton Gardens and presidential palace (part-time)

Radisson Blu Golden Sands, Next to one of the best sandy beaches as well as having a good pool complex. Not much else around it, but as I live locally I was there yesterday at the Essence restaurant which is a pretty good fine dining experience. There are plenty of other bars and restaurants there, or take a bus or taxi to St Pauls Bay/Bugibba (I highly recommend the Tarragon restaurant) or Mellieha. Both are only 10 minutes away. Note that there is another Radisson at St Georges bay (near Paceville), which I think is not as nice and somewhat bland.

Kempinsky San Lawrenz on the island of Gozo is top notch, but a place to chill and not party.

I suggest that you go for one of the Paceville properties if you want to have a party on your 30th birthday. That means Hilton, Westin Dragonara, or Intercontinental. Remember that there are casinos at the Westin and Hilton (and possibly others) if that makes a difference.
The Le Meridien at St Julians/Balluta is also in a restaurant/pub area, but you'd want to got to Paceville if you want a club.

I hope this helps.